Adsorptive removal of Cr(vi) from wastewater by α-FeOOH hierarchical structure: kinetics, equilibrium and thermodynamics

A novel hollow urchin-like α-FeOOH hierarchical structure was fabricated via a one-pot hydrothermal procedure without using any templates, surfactants or organic raw materials. An inside-out amorphous ripening mechanism was proposed to unravel its structural evolution. The kinetics, equilibrium and thermodynamics of its adsorptive removal of Cr( vi ) from wastewater were comprehensively investigated. It was found that the adsorption process can be depicted using a pseudo-second-order model, and a high adsorption capacity of 58.97 mg g −1 was obtained from the equilibrium adsorption isotherm. Also, the thermodynamic parameters ( i.e. , enthalpy, entropy and Gibbs free energy) at different temperatures were acquired to reveal a spontaneous adsorption process, with both physical and chemical characteristics. The Cr( vi ) adsorptive performances (including adsorption kinetics, equilibrium isotherms and thermodynamics) of hollow urchin-like α-FeOOH hierarchical structure were comprehensively studied.